A vacuum cleaner is an electromechanical appliance utilized to effect the dry removal of dust, dirt and other small debris from carpets, rugs, fabrics or other surfaces in domestic, commercial and industrial environments. In order to achieve the desired dirt and dust removal, most vacuum cleaners incorporate a rotary agitator. The rotary agitator is provided to beat dirt and debris from the nap of the carpet or rug while a pressure drop or vacuum is used to force air entrained with this dirt and debris into the nozzle of the vacuum cleaner. The particulate laden air is then drawn into a dirt collection vessel. The air is then drawn through a filter before being directed through the motor of the suction generator to provide cooling. Finally, the air is filtered to remove any fine particles of carbon from the brushes of that motor or other dirt that might remain in the airstream before being exhausted back into the environment.
Often the dirt collection vessel is designed to produce cyclonic airflow by providing that vessel with a dirt chamber having a cylindrical sidewall and a tangentially directed air inlet. This arrangement forces the air to swirl around the dirt collection chamber in the manner of a cyclone. The centrifugal force that is produced causes dirt and debris to move toward and against the cylindrical sidewall of the chamber while relatively clean air may be drawn off from the center of the chamber through the filter toward the suction generator.
Under most operating conditions most or all of the dirt and debris is removed from the airstream by the cyclonic airflow. At times, however, some dirt and debris remains entrapped within the airstream. Typically, that dirt and debris is relatively fine dirt particles of light weight which are not as susceptible to the centrifugal separation force produced by the cyclonic airflow. Over time such fine particles may become entrapped and fill the pores of the filter media thereby restricting airflow and reducing the cleaning efficiency of the vacuum cleaner. Eventually the cleaning efficiency of the vacuum cleaner becomes so impaired it is necessary for the operator to either clean or change the filter in order to achieve the desired level of cleaning. The present invention relates to a vacuum cleaner, extractor or the like equipped with a more efficient and effective filter cleaning mechanism. Advantageously, the present invention allows one to quickly and easily clean dirt and debris from a filter including particularly fine particles from the pores of the filter. As a result each filter has a longer service life and the apparatus may be operated at a higher cleaning efficiency over the entire length of that extended service life.